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<body>
    我在这个页面去访问别的站点的数据
    这个时候回产生跨域
    <script>
        
        var xhr = new XMLHttpRequest();
        xhr.open("get","http://api.jisuapi.com/sms/send?mobile=13246324843&content=用户您好。【极速数据】&appkey=835b04488704f2ab");
        
        xhr.send(null);
        xhr.onreadystatechange=function(){

            if(xhr.readyState == 4 && xhr.status == 200){
                var data = xhr.responseText;   
                alert(data);
            }
        }
    
    </script>
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